Add tests for closing a frame within the scope of a getusermedia callback.

content/test/data/media/webrtc_test_utilities.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // These must match with how the video and canvas tags are declared in html.
 const VIDEO_TAG_WIDTH = 320;
 const VIDEO_TAG_HEIGHT = 240;
 
 // Fake video capture background green is of value 135.
 const COLOR_BACKGROUND_GREEN = 135;
 
 // Number of test events to occur before the test pass. When the test pass,
 // the function gAllEventsOccured is called.
 var gNumberOfExpectedEvents = 0;
 
 // Number of events that currently have occurred.
 var gNumberOfEvents = 0;
 
 var gAllEventsOccured = function () {};
 
 // Use this function to set a function that will be called once all expected
 // events has occurred.
 function setAllEventsOccuredHandler(handler) {
   gAllEventsOccured = handler;
 }
 
 // Tells the C++ code we succeeded, which will generally exit the test.
 function reportTestSuccess() {
-  window.domAutomationController.send('OK');
+// If a test is reported to succeed and later a crash occurs

[phoglund_chromium, 2015/04/10 09:47:58]

Well, it's not "in the scope of the timer", it's rather we enqueue a new
javascript task after the current task completes. What about phrasing it like
this:

This function enqueues sending an OK back to the test, rather than doing it
directly. We do this so we catch crashes that occur in the current execution
context, but after reportTestSuccess is invoked.

[perkj_chrome, 2015/04/10 09:57:29]

Done.

+// after the reporting JavaScript has completed, the test will pass.
+// By completing the test in the scope of a timer, the reporting
+// JavaScript will finish and if that leads to a crash, it happens
+// before the test is reported to pass.
+  setTimeout(function () {
+    window.domAutomationController.send('OK');
+  }, 0);
 }
 
 // Returns a custom return value to the test.
 function sendValueToTest(value) {
   window.domAutomationController.send(value);
 }
 
 // Immediately fails the test on the C++ side.
 function failTest(reason) {
   var error = new Error(reason);
@@ skipping 181 matching lines @@
     devices.forEach(function(device) {
       if (device.kind == 'video')
         hasVideoInputDevice = true;
     });
 
     if (hasVideoInputDevice)
       sendValueToTest('has-video-input-device');
     else
       sendValueToTest('no-video-input-devices');
   });
-}
+}